Conventional wet cell storage batteries contain acid electrolytes such as sulfuric acid. A long standing problem with such batteries is the tendency of the acid contained therein to leak out or condense on the battery surfaces, thereby causing corrosion of the battery terminals, battery cables, battery holder or support, and any other metallic parts in the vicinity.
In order to combat this problem numerous proposals have been set forth. For example, U.S. Pat. No. 3,661,642 to Pisturo discloses a method for cleaning corroded battery terminals and the like by applying an aqueous solution of pure fruit dye, sucrose, sodium bicarbonate, benzoate of soda and vitamin D3 to the battery terminals followed by flushing with water. However, such a method is useful only after corrosion has manifested.
In order to prevent the formation of corrosion, U.S. Pat. No. 2,564,810 to Martin et al discloses a battery terminal cover that protects the terminals and the battery clamps. The cover contains an interior pad, made of fabric or porous material such as felt, that is impregnated with bicarbonate of soda or other suitable chemical. This interior pad serves to neutralize the escaped acid near the terminals.
Similarly, U.S. Pat. No. 3,224,906 to Diebel discloses an acid-resistant material for use in protecting battery terminals and the like from corrosion. In this method, a material, which is porous and has been impregnated with a basic substance, is placed around the battery terminals and/or the periphery of the outer top edge of the battery. As the escaped acid migrates toward the battery terminals or the edge of the battery, it encounters the impregnated material and is neutralized; thus protecting the various metallic parts. In one embodiment, compressed glass fibers are impregnated with a solution of natural rubber latex and sodium carbonate. After drying, the material can then be cut into washers, for use on the battery posts, or into strips, for use around the top edges.
A slightly different approach for protecting metallic parts around the battery calls for encasing the entire battery with a battery cover, as is shown in U.S. Pat. No. 3,825,447 to Kraals. The primary object of this method is to prevent corrosive damage that could be caused by acidic emanations from the battery through shear containment. The battery cover is an enclosed container having sidewalls, a bottom and a top wall with a closure device thereon. The battery cables are connected to the battery terminals through two openings in the sidewalls. The cover is then sealed to prevent the escape of any vapors or acid from the interior of the cover. The cover is made of polyethylene which does note serve to neutralize the escaped acid.
Of the various methods discussed above, none have been completely effective and convenient in protecting metallic parts from the corrosive effects of battery acid. While the protective material of Diebel et al. is useful for neutralizing acid present on the top surface of the battery, any acid passing the protective border around the upper edge of the battery can still leak to the battery holder or other parts thereof and cause substantial damage. Moreover, such a protective border offers no protection from acid that diffuse or leaks through the sides or bottom of the battery. A battery cover is effective but inconvenient since it is difficult to use and restricts easy access to the battery itself. Moreover, such devices are potentially hazardous as they contain trapped acid which may leak out during servicing or replacement.